2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/10912A geometrically thin, optically thick, warped accretion disk with a central source of luminosity is subject to non-axisymmetric forces due to radiation pressure; the resulting torque acts to modify the warp. Initially planar accretion disks are unstable to warping driven by radiation torque, as shown in a local analysis by Pringle (1996) and a global analysis of the stable and unstable modes by Maloney, Begelman, & Pringle (1996). In general, the warp also precesses. We discuss the nature of this instability, and its possible implications for accretion disks in X-ray binaries and active galactic nuclei. Specifically, we argue that this effect provides a plausible explanation for the misalignment and precession of the accretion disks in X-ray binaries such as SS 433 and Her X-1; the same mechanism explains why the maser disk in NGC 4258 is warped.10 pages, latex, paspconf.sty (included), 3 figures. To Appear in Proceedings of IAU #163, "Accretion Phenomena and Associated Outflows", (cf. also astro-ph/9612110, which also appears in ApJ, 472, p. 582)Astrophysicstext